a json parse tutorial which just for learn how to parse json string
- parse json string, store in json node tree, which contains type:
* null
* boolean: false or true
* number: store it in double
* string
* array: json
* object: key, value list. - store all the information in json node.
- generate json string by json node.
- compare json node, check if they are equals or same one.
- copy json node with deep copy mode.
finish it at 2020/01/14